Contact structure for electric switches



. Dec. 25, 1928. 1,696,301

T. T'. GREENWOOD CONTACT STRUCTURE FOR ELECTRIC SWITCHES Filed May 29, 1925 Patented Dec. 25, 1928.

um'r eosrAfrlas TALMA T. GREENWOOD, OF EAST TEMPLETON, MASSACHUSETTS, ASSIGNOB, BY MESNE PATENT OFFICE,

ASSIGNMENTS, TO CONDIT ELECTRICAL MANUFACTURING.CORPORATION, OF BOS- TON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

CONTACT STRUCTURE FOR ELECTRIC SWITCHES.

Application filed May 29, 1925. Serial No. 33,847.

This invention relates to electric switches of the down-break t and has for an object the provision of means to improve the contact between the separable switch members when they are'traversed by a heavy current.

A further object is" generally to improve the construction and operation of electric fixed to the lower ends of said studs and are provided with lower contact faces 16 which,

in accordance with this invention, are inclined downwardly and outwardly.

The movable switch member includes a laminated, or brush, member formed with the intermediate, or body section 18 and the upwardly directed toe-section's 20 which are disposed approximately at right angles with the intermediate section. In accordance with this invention, the toe sections are formed or provided with upper contact faces 22 approximately conformed with the contact faces 16, or inclined downwardly and outwardly. Preferably the toe-sections are adapted to make contact with the fixed contact members approximately in the line of the studs 10. As thus arranged, the magnetic effect of the cur renttraversing the switch tends to force the yielding toe-sections of the brush member outwardly against the downwardly and out wardly inclined contact faces of the fixed contact members, whereby to improve the contact pressure under load.

The laminae of the brush member are adapted to yield in a downward direction under the pressure exerted upon them by the switch mechanism, but the amount of yielding movement is limited by the spacer plate 23 and the limit-plate 24. Said limit plate is provided with up-turned end-portions 26 which overlie the toe-sections of the brush member and support the toe-sections against undue yielding in an outward direction due to the magnetlc reaction of the current traversing the switch.

The structure may be otherwise modified without departing from the spirit of the invcntion.

I claim: I

1. An electric switch having a fixed contact member provided with an inclined lower contact face, and a yielding movable switch member comprising a brush member adapted to engage said contact face, the inclination of said contact face and the disposition of the switch members being such as to support said yielding brush member against deleterious lateral displacement due to the magnetic re action thereon of the current traversing the switch.

p 2. An electric switch having a. stud terminated in a fixed contact member provided with an inclined lower contact face, and a yielding movable switch member comprising a brush member having its end portion arranged in line with said stud and adapted to engage said contact face approximately in the line of said stud, said inclined contact face characterized by having an inclination in a direction to support the end portion of the brush member against lateral displacement therefrom due to magnetic forces set up by the current traversing the switch.

3. An electric switch having a pair of stationary switch members terminated in fixed contact members provided with downwardly and outwardly inclined contact faces, and a movable switch member including a brush member disposed below said fixed contact members and having upwardly directed toesections provided with downwardly and outwardly inclined contact faces arranged to engage the contact faces of said fixed contact members, the inclined contact faces of said fixed contact members characterized by providing abutment faces against which the toesections of said brush member are pressed by the magnetic forces acting in said toe-porllll movable sn'itc member dis iosed )(JS and t sec ions prorid e inclined age the contact of R11 a 1 membe said toe-sections g and fixed contact r in the le of said st: 1 clincd cont-ac "ed con at S,

ar sn'il 11 mediate sections J .t actions downwardly and out- Wardly inclined contact faces adapted to en gage the contact faces of said fixed contact members approximately in the line of said stationary switch members the inclined contact faces of said fixed contact members char actcrized by providing abutment faces against which the toe-sections of said brash n nnbe are pressed by the magnetic forces acting in said toe-portions.

(i. A contact member for an electric switch including a laminated flexible member having an inte mediate horizontal section and opposed \ertically extended mid-sections terminated in t'lownwardly and outwardly inclined contact faces.

7. A movable switclrmember to an electric Yitt'll including a laminated member having TALMA '1. GREENWOOD. 

